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issue in OWL SS&FS and bug in mapping from RDF graphs

From: Patel-Schneider, Peter <Peter.Patel-Schneider@nuance.com>
Date: Fri, 11 Apr 2014 21:09:14 +0000
To: "public-owl-comments@w3.org" <public-owl-comments@w3.org>
CC: Boris Motik <boris.motik@cs.ox.ac.uk>
Message-ID: <B9A8436B-1520-4D8B-BB1C-FF1F5ED0CBC3@nuance.com>
The OWL Structural Specification and Function-Style Syntax states for most syntactic constructs with an arbitrary number of arguments that these arguments are considered to be a set under structural similarity.

This causes no problems for many of these syntactic constructs but there are a few where removing duplicates changes the meaning of the construct.

For example, according to the wording in section 9.1.3 of SS&FS

DisjointClasses( ex:foo ex:foo ex:bar )

implies that ex:foo is empty, which is very different from 

DisjointClasses( ex:foo ex:bar )

It would not be easy to simply change these constructs to take multisets because the OWL API would have to be changed.

I propose the following fix:

1/ The functional-style syntax requires that the arguments to DisjointClasses, DisjointObjectProperties, DisjointDataProperties, and DifferentIndividuals and all but the first argument to DisjointUnion all be structurally different.

2/ When converting the triple x owl:disjointWith y where x and y are structurally similar the axiom SubClassOf( CE(x) owl:Nothing ) is produced.

This is not an ideal fix by any means, but a better fix would require much more significant changes in deployed software.

Peter F. Patel-Schneider
Received on Friday, 11 April 2014 21:09:42 UTC

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